There are essentially two types of machining simulation known for machine tools. In one type the path of a theoretical tool tip is represented as a line on the screen of an NC control means; this type is therefore also called line graphics. In the second, the area of a shaded image of a workpiece that overlaps a simplified representation of a tool contour is deleted from the screen--this type is also called deletion graphics. Both types are described in EP-B 0 129 091. They serve to monitor the risk of collisions and also show up serious programming errors.
The representation of the results of machining for an erosion machine is described in EP-A 308 727. The control means calculates the part of the workpiece cut away for each machining command and stores the shape of the cutout. Addition of all the cutouts gives the finished workpiece. The workpiece and the cutouts are shown.
A modification of the line graphics results if the theoretical cutting tip rotates and simultaneously carries out a feed movement As can be seen in Zeitschrift fur Metallbearbeitung, 83, 1989, Vol. 11-12, pages 56-58 and in Werkstattstechnik 78 (1988), pages 97 to 99, this gives a two-dimensional impression which makes it possible to detect collisions and unfavourable tool shapes as well as unmachined regions. However, this simulation method is only suitable for milling operations, wherein the view of the workpiece must lie in the direction of the milling axis.